The detained Burmese opposition leader Aung San Suu Kyi will be put on trial today in connection with the intrusion of an American man who sneaked uninvited into her compound, a spokesman for her party said.

Nyan Win said he was informed of the plan to try Suu Kyi and two women who live with her by her lawyer, Kyi Win. The lawyer said the three will be taken early this morning to Rangoon's Insein prison, but he was not told what charges they would face.

An American, John William Yettaw, was arrested last week for allegedly swimming a lake to secretly enter Suu Kyi's home and stay there for two days. His motives were unclear.

Nyan Win said the authorities would pick the three women up from Suu Kyi's lakeside home at 7am (midnight GMT) to appear before the court.

He added that it was possible that Suu Kyi might not immediately be returned to her house, as arrangements have been made to take care of it in the absence of the women, who live there alone.

When a person is put on trial, he or she is normally held in a police cell for up to 14 days, but in special cases defendants are held at Insein, in the north of the city.

Yettaw's intrusion last week raised fears that the Nobel Peace laureate might have been ensnared in activities that could put her in further legal trouble.

The junta demands of all Burmese that local officials are notified about any overnight visitor who is not a family member. The law says foreigners are not allowed to spend the night at a local's home.

Some members of Suu Kyi's party, the National League for Democracy, have been jailed for about two weeks for violating that law.

Suu Kyi has already spent more than 13 of the last 19 years – including the past six – in detention without trial for her nonviolent promotion of democracy, despite international pressure for her release.

She has recently been ill, suffering from dehydration and low blood pressure. Dr Pyone Moe Ei was allowed to see her on Monday afternoon, and Nyan Win had said on Tuesday that her medical condition had improved after the doctor administered an IV drip.